evm-token-decimals

# EVM Token Decimals Silent decimal mismatches are one of the easiest ways to ship balances or USD values that are off by orders of magnitude without throwing an error. ## When to Use - Reading ERC-20 balances in Python, TypeScript, or Solidity - Calculating fiat values from on-chain balances - Comparing token amounts across multiple EVM chains - Handling bridged assets - Building portfolio trackers, bots, or aggregators ## How It Works Never assume stablecoins use the same decimals everywhere. Query `decimals()` at runtime, cache by `(chain_id, token_address)`, and use decimal-safe math for value calculations. ## Examples ### Query decimals at runtime ```python from decimal import Decimal from web3 import Web3 ERC20_ABI = [ {"name": "decimals", "type": "function", "inputs": [], "outputs": [{"type": "uint8"}], "stateMutability": "view"}, {"name": "balanceOf", "type": "function", "inputs": [{"name": "account", "type": "address"}], "outputs": [{"type": "uint256"}], "stateMutability": "view"}, ] def get_token_balance(w3: Web3, token_address: str, wallet: str) -> Decimal: contract = w3.eth.contract( address=Web3.to_checksum_address(token_address), abi=ERC20_ABI, ) decimals = contract.functions.decimals().call() raw = contract.functions.balanceOf(Web3.to_checksum_address(wallet)).call() return Decimal(raw) / Decimal(10 ** decimals) ``` Do not hardcode `1_000_000` because a symbol usually has 6 decimals somewhere...